Apparatus for projecting molten pulverized bodies



A ril 16, 1935. F. P. c. BENOIT 1,993,217

APPARATUS FOR PRQJECTING MOIJTEN PULVERIZED BODIES Filed Feb. 25, 1933 3 Sheets-Sheet l April 16, 1935. I F P c, BENCH 1,998,217

APPARATUS FOR PROJECTING MOLTEN PULVERIZBD BODIES Filed Feb. 25, 1933 .3 Sheets-Shet 2 Apnl 16, 1935. F. P. c. BENOIT 1,993,217

APPARATUS FOR PROJECTING MOLTEN PULVERIZED BODIES Filed Feb. 25, 1933 3 Sheets-Sheet 3 Fig.9 42

aa kbmm FYQZMJMMWWW ears APPAT'US FOR PRGJECTKNG MGLIFEN EULVERHZED ROBLES Francois Philippe Charles Benoit, Paris. France Application February 25, 1933, Serial No. 658,531 lln France June 23., 15932 3 Claims.

This invention relates to a process of and apparatus for projecting at high speed molten and pulverized bodies on articles to which is to be applied a coating layer.

The processes and apparatus generally heretofore employed use metals in the form of ribbons or filaments and suffer from the drawback that on the one hand the metal is melted slowly and non-uniformly and that on the other hand there are projected relatively voluminous particles of irregular form admixed with air bubbles. But if the metal is previously reduced to the form of an impalpable powder, not only is fusion efiected more easily and rapidly, but it is also more regular and gives extremely fine deposits.

The process according to the invention, consists in first bringing the bodies to be projected into a state of very fine division by any suitable treatment suitable for the body in question and then in bringing these bodies into suspension in a current of compressed air with a continuous whirling movement, without suction, to a blow pipe or pistol for effecting fusion and projection.

In consequence. the fusion of the bodies in an atomized state is effected rapidly, regularly and easily, so that it is practicable to project hard metals of high fusion points, such as copper, bronze, nickel, iron, steel. tungsten, etc., on any surfaces to be metallized, as well as other non-metallic bodies which are fusible with difficulty, such as silica and quartz for example, to obtain vitreous coatings. It is thus possible to produce enamels of suitable consistency and colour by making powdered silica or powdered quartz and metallic powders or powders of suitably chosen metallic oxides.

In order that the pulverization may be regular and effected without oxidation, reducing substances may be incorporated in the metallic powders.

On the other hand, during projection of the atomized materials their penetration into the art-i=- cles to be coated, if more or less permeable such as fabrics, hides and wood, may be facilitated by setting up at the face opposite that to be coated with the pulverized material a powerful attractive force, for example by means of an electro-mag'net when metal is being projected, or by means of a suction fan.

With the adoption of the process there may be obtained coating of hard metals of variable thickness which are very dense and adherent and of extremely fine grain by utilizing metallic powders or mixtures of metallic powders. Vitreous coatings and enamelled coatings may be produced on any surfaces to render them non-combustible and (m. int-12.2)

able to resist attack. by corrosive substances and oxidation; particularly the enamelling gives varied decorative effects.

As the coatings obtained are constituted by particles of great fineness, these coatings may be applied not only to solid rigid bodies but also to yielding bodies, and even to deformable bodies such as elastic bodies, plastic bodies and soft bodies. There may be thus obtained a wide range of new industrial products among which may be mentioned apparatus, instruments and articles for medical and surgical use.

The improved apparatus for performance of the process comprises three main parts, namely a powder reservoir, a tube for effecting suspension of the powder in air and for leading it to the blow pipe, and a pistol used for projection.

The blow pipe is fed by three tubes supplying acetylene, oxygen and compressed air. or other combustible and combustion-supporting media. These tubes are fitted with cocks which are separately controlled for obtaining, depending on the powders used, flames of different temperatures, but in case of need they may be also adapted to be closed simultaneously. The propulsion and control of the supply of powder are ensured by the compressed air coming from the powder receptacle the delivery from which latter is controllable.

Fig. l is an axial section of the powder reservoir.

Fig. 2 is a plan of the lower half of this reservoir.

Fig. 3 represents partly in section a modified form of one of the internal fitments of the reser- Fig. 4 is a view in longitudinal axial section of the device for conducting the powder to the blow pipe burner.

Figs. 5, 6 and 7 are perspective views of different constructions of helicoidal vanes for imparting a whirling movement to the air stream.

Fig. 8 is a view of the burner seen from the rear.

Fig. 9 is a side elevation of the pistol with means for cooling the stream.

Fig. 10 is a perspective view showing separately the cooling device.

Referring to Fig. 1, it will be seen that the powder reservoir is constituted by a receptacle formed in two parts i and 2 interconnected at 3', for example, by interengaging screw threads. of

which the lower part 2 receivesthe reserve of powder introduced by the funnel 4 adapted to be closed by the stopper 5.

At the moment of use the powder is put in suspension in a current of air introduced into the receptacle 2 by the conduit 6 connected to a source of supply of compressed air which is not shown and which may be heated by a suitable device also not shown. This compressed air. the delivery of which is controlled by means of the cock I, enters the tubular column 8 and passes along the lateral branches a which terminate in nozzles Hi and which also present small orifices in the form of nipples ll; these branches El are of substantially helicoidal form so that the jets of compressed air which escape from the orifices W. H are given a turbulent movement in the reser voir 2 and thereby are caused to entrain the powder in a state of suspension.

The air charged with powder enters the upper part i of the reservoir where it meets the dispersing cone l2 in the form of an inverted dish or funnel which brakes and steadies the current of powder-laden air which latter then escapes by way of the orifices E3 in the tube i l that supports the disperser l2 and terminates exteriorly of the reservoir in a nipple l5 connectible by a, rubber tube, for example. to the pistol or gun used for projecting the powder.

To permit control of the posit-ion of the disperser $2 fixed to the lower end of the tube i l, the said tube. which is threaded at it? is screwed into a cover l"! which in turn is screwed on to the receptacle l. The tube It is adjusted to suitable position causing it to penetrate the cover l? more or less and is fixed in position by means of the nut 18 provided with wings id.

The base 20 of the lower receptacle 2 which is represented separately in plan in Fig. 2 is screwed on to the receptacle and carries the tube 8 with the cock "I: it is adjusted by means of the pegs 26, it being understood that these details may be varied.

The powder reservoir is provided with a collar 22 provided with pivots or gimbals 23 so that it may be hung vertically. for example, by means of a device of the Cardan type, itis also provided with means not shown of any known type for imparting vibrations thereto in order to facilitate dissemination of the powder.

Fig. 3 shows a. modified construction of the disperser. The tube 54 with the orifices iii and the cover 57 are similar to the corresponding elements of the first described construction, but the disperser proper indicated at l2 is replaced by a body of revolution E i presenting substantially the form of two truncated cones united at their bases by a toroid. The profile of this disperser may be varied depending, for example, on the nature of the powder used.

As already stated, the powder reservoir is connected by a rubber tube not shown to a device adapted to ensure whirling movement, such device being represented in longitudinal section in Fig. 4. The rubber tube is fixed to a nipple at the free extremity of the tube 25 which is shown hatched in Fig. 4. This tube 25 which terminates in a cone 26 opens into a first chamber 27 of ovoid internal profile. In order to be able to regulate the extent of its penetration into this chamber the tube 25 is screw-threaded and engages the correspondingly threaded wall of the chamber, being fixed in poition by jam nuts 28.

In the chamber 2'! is arranged a first series of helicoidal vanes 29 which are fixed to a ring till and which give to the air a gyratory or whirling movement. To hold the ring 39 in place so that it may be exchanged when desired. the chamber 27 is formed in two parts screwed one on to the other at 3i and nipping the ring 30 between them.

A constriction 221a separates the chamber 2'! from the second similar chamber 32 also formed in two parts which are screwed on to one another at 33 and which nip between them a ring 36 carrying hellcoidal vanes 35; these vanes are welded to a boss 35 of stream-line form of which the ogival head 36a is presented to the air stream so as to direct it towards the peripheral wall while avoiding the formation of eddies.

These devices for producing a whirling movement of the air stream may be modified to suit the nature of the powder used. By way of example certain modified constructions are shown in Figs. 4, 5, 6 and 7. They comprise generally helicoidal vanes fixed to a ring either directly or through the medium of a truncated conical ferrule; they are arranged to be interchangeable and may be mounted selectively in one or other of the chambers ill and When leaving the chamber 32 the air current flows through a passage 3! bored axially in a. 1

cylindrical tube 35 which is fixed by a screw thread 39 on to the part 20 solid with the handgrip or butt all of the pistol burner (Figs. 8 and 9) The blow pipe burner consists of a circular box 42 to the under side of which are fixed three separate tubes 33 serving respectively for the passage of compressed air, oxygen and acetylene in the case of an oxy-acetylene burner and supplied through rubber tubes fixed to the connections 44. Each of these tubes #43 is provided with its own regulating cock, while an additional operating device is provided for effecting the simultaneous closing or opening of the three cocks by means of the index finger of the hand holding the burner. Passages formed in the body of the box 42, preferably concentric with one another, lead the gas 'to the tip of the burner 46; further, a passage in the burner forming a prolongation of the passage 3'8 leads to the nose of the burner the compressed air which entrains the powder in suspension.

The three regulating cocks are fitted with pointers 65a each moving over a dial.

Simultaneous closure of the cocks is effected by three arms 59 articulated to a common bridgepiece so solid with a trigger 58 which may be operated by the index finger of the hand which holds the handle 4 i.

In Fig. 9 there is indicated a cooling device which is represented separately in perspective in Fig. 10 and which has for its object to permit the fusion of pulverized metals or other bodies requiring a very hot flame and their projection on to articles very sensitive to heat such as paper, fabrics, skins, leather, plastic materials and moulded materials.

This cooling device is composed of two lateral tubes ll each flattened to form a nozzle at its free extremity 48 and welded or otherwise fixed at #39 to a collar 50 incorporated in the rear part of the burner. This collar 50 may be fixed to the burner by a screw 5 with a finger-operated head 52 (Fig. 10) or by any other equivalent device.

Compressed air enters by way of the conduit 53 fixed to the collar 50 in which latter are pierced channels which establish communication between the supply tube 53 and the tubes 41. Regulation of the quantity of air is effected by a cock 54. A connection 55 permits the device to be connected to a source of supply of compressed air.

It is advantageous to be able to vary the position of the nozzles 48 relatively to the head of the blow pipe or to be able to vary the spacing of the nozzle 48. With this object the tubes may have a certain elasticity either on account of the nature of the constituent metal or by reason of their form or their mode of attachment to the collar 50, while means is provided for moving them towards or away from one another.

By way of example, Fig. 10 shows the nozzles 48 as being solid with arms 56 having internally threaded orifices engaged by a tum-buckle member 51 having screw threads of opposite hand at its two ends and adapted to be turned by means of a finger-piece 6|. This device permits the projection of a jet of cold compressed air parallel to the jet of metallic vapours, thus conserving for the jet all its metallizing power without altering even the most delicate substances.

What I claim is:-

1. Apparatus for use in projecting in a molten atomized state hard bodies fusible with difficulty, comprising, in combination with a blow-pipe burner, connections for supply of combustible and combustion-supporting media to said burner, a reservoir comprising interconnected upper and lower receptacles. said lower receptacle serving as a container for powder, means for introducing a regulatable quantity of'i'zompressed air into said lower receptacle, means for setting up a. whirling current of air in said lower receptacle to bring the powder therein to a state of suspension, 2. disperser in the upper receptacle, and a connection between said upper receptacle and said burner for leading to said burner a stream of air carrying powder in suspension.

. 2. Apparatus as claimed in claim 1 in which the means for setting up a. whirling current of air within the lower receptacle comprises an air supply pipe with helicoidal branches terminating within said lower receptacle.

3. Apparatus as claimed in claim 1 in which there is interposed in the connection between the upper receptacle and the burner a succession of ovoid chambers containing sets of helicoidal vanes.

FRANCOIS PHILIPPE CHARLES BENOIT. 

